7/16"-20 18-8 Stainless Steel Fine Thread Type C Lock Nuts (6 pcs.)

Diameter: 7/16"
Diameter 2: 25/32"
Thickness: 3/8"
Material: Stainless Steel
Driver Type: 11/16" Wrench
Thread Size: 20 (Fine)
Hardness: 18-8
Style: Type C
Type: Lock Nut

Box of 6.

A lock nut is a nut that resists loosening under vibrations and torque.